I don't know if the European Apple-tax makes this tenable, but I just sell my MBP on EBay every year or two. A 16-month old MBP 13.3" is selling for about 70% of its original price on EBay. If you do this three times in four years, you'll have paid about as much as the original price of the machine, for about as long as you were going to keep the machine anyway, but will get little upgrades over time as Apple upgrades that model #.